This is kind of... Well, good news, I suppose? It depends on where you allegiances lie, but it seems like Ubuntu is warming up to the idea of using Qt to develop applications. It's no secret that Qt is a far more advanced development framework than Gtk+, so it only makes sense for Ubuntu - a GNOME/Gtk+ distribution - is looking at it.

Trying to write a GTK+/GNOME app can lead to multiple coding styles, multiple API styles, tonnes of dependencies, and so on.

It's the different between using an IDE for coding, and using a mishmash of editors and command-line tools.

Not sure it's a good comparison. In some cases (e.g. when you really need fine-grained control on the compilation + linking process, like in kernel development), going text editor + command line is just the best option. In other (arguably most) cases, it's IDEs which rock. One should use the right tools for the right job.

On the other hand, I can't think of a situation where tons of dependencies with various coding styles could be a good thing.